Future of industrial motors: Permanent Magnet

By K Pitso, Danfoss


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Published in:

Electricity+Control, March 2013 (pages 27 - 29)

Enquiries: Tel. 27 (0) 785 7607 or email: pitsok@danfoss.co.za


Compared with the prolific induction motor (IM), permanent magnet (PM) motors provide efficiency and reliability and have the additional advantages of higher power density (power per mass or volume), superior power factor (low current), low rotor temperature, and synchronous operation. Advancement in magnet technologies allows operation at higher temperatures without permanent magnetisation loss.

PM motors are economically viable because of the availability of rare-earth magnets, such as neodymium iron and boron, at lower prices. Three-phase induction motors have been widely recognised as the best option for industrial applications in various industries. Over the past 30 years, there have been clear trends in motor utilisation that demand higher power density and increased energy efficiency. In many industry applications, motor size and inertia are critical.


Take note:

  • Permanent magnet motors offer a number of significant advantages.
  • These motors have become more economically viable because of the availability of rare-earth magnets.
  • Permanent motor machines can be used with a VSD, providing improved efficiency.